[Downloads UI] Add histograms for file extensions

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java
index 4a58bc937d2e03f0deadd5c8c3324fa98216d712..43f99ff2c541938a78ff254bca69a6ba6dfce696 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java
@@ -110,7 +110,16 @@ public class DownloadHistoryAdapter extends DateDividedAdapter implements Downlo
 
         for (DownloadItem item : result) {
             DownloadItemWrapper wrapper = createDownloadItemWrapper(item);
-            if (addDownloadHistoryItemWrapper(wrapper)) itemCounts[wrapper.getFilterType()]++;
+            if (addDownloadHistoryItemWrapper(wrapper)
+                    && wrapper.isVisibleToUser(DownloadFilter.FILTER_ALL)) {
+                itemCounts[wrapper.getFilterType()]++;
+                if (!isOffTheRecord && wrapper.getFilterType() == DownloadFilter.FILTER_OTHER) {
+                    RecordHistogram.recordEnumeratedHistogram(
+                            "Android.DownloadManager.OtherExtensions.InitialCount",
+                            wrapper.getFileExtensionType(),
+                            DownloadHistoryItemWrapper.FILE_EXTENSION_BOUNDARY);
+                }
+            }
         }
 
         if (!isOffTheRecord) recordDownloadCountHistograms(itemCounts);